Compensating linkage

ABSTRACT

The present invention envisions apparatus for rotating a pair of aligned shafts in equal arcs while allowing relative rotary motion of the shafts. In one embodiment, apparatus embodying the invention may comprise elongated linking means which has positioned on each end thereof a universal joint. An arm may be rigidly secured to each of the aligned rotary shafts and each of the arms thus secured may be operatively connected to one of the universal joints located at the end of the elongated linking means. A power assembly may be provided for moving the linking means in an arc about the parallel shafts thereby rotating the shafts. The power assembly is characterized by means for connecting a portion thereof with a central portion of the linking means in such a manner as to allow pivotal motion of the linking means relative to the power assembly. In addition, a portion of the power assembly is designed to allow limited universal motion of the elongated linking means about an axis normal to the longitudinal axis of the linking means.

United States Patent [72] Inventor Eldon L. Rikli R.R., Drummond, Okla.73735 [21] Appl. No. 815,989 [22] Filed Apr. 14, 1969 [45] Patented Mar.16, 1971 [54] COMPENSATING LINKAGE 4 Claims, 4 Drawing Figs.

[52] US. Cl 172/580, 172/619,172/668,172/675 [51] Int. Cl A0lb 21/08,AOlb 65/06 [50] Field of Search 172/619,

FOREIGN PATENTS 1,365,467 5/1964 France Primary ExaminerRobert E;Pulfrey Assistant Examiner-Stephen C. Pellegrino Atrorney- Dunlap,Laney, Hessin & Dougherty ABSTRACT: The present invention envisionsapparatus for rotating a pair of aligned shafts in equal arcs whileallowing relative rotary motion of the shafts. In one embodiment,apparatus embodying the invention may comprise elongated linking meanswhich has positioned on each end thereof a universal joint. An arm maybe rigidly secured to each of the aligned rotary shafts and each of thearms thus secured may be operatively connected to one of the universaljoints located at the end of the elongated linking means. A powerassembly may be provided for moving the linking means in an are about74/96 the parallel shafts thereby rotating the shafts. The powerassembly is characterized by means for connecting a portion [56]References cued thereof with a central portion of the linking means insuch a UNITED STATES PATENTS manner as to allow pivotal motion of thelinking means relal,329,598 2/1920 Hegland 172/579X tive to the powerassembly. In addition, a portion of the power 2,755,720 7/1956Markel..... l72/462X assembly is designed to allow limited universalmotion of the 3,050,882 8/1962 Chattin l72/407X elongated linking meansabout an axis normal to the longitu- 3,19.4,323 7/1965 Zimmerman 172/500dinal axis of the linking means.

58 5; 25/: 23a, 2 k I? 36 we ma I fi/a 35 38 [8a 4a 4a g9 49/.) 49a o oas COMPENSATING LINKAGE BACKGROUND OF THE INVENTION One of the morecommon types of farm implements currently in use is the grain drillwhich, as generally constructed, includes a pair of aligned disc gangswhich may be raised or lowered by a power mechanism, such as a powercylinder. For this purpose a linkage mechanism is commonly provided tointerconnect each of the disc gangs with the power mechanism andsvitheach other.

when such grain drills are used on relatively flat land surfaces noproblems are encountered insofar as the linked motion of the two discgangs is concerned. When, however, relatively high or low portions ofthe land are encountered by one of the disc gangs but not the otherthere is a tendency of the gangs to move as a unit upwardly ordownwardly to accommodate to the change in elevation of the groundbeneath one of the gangs. When this occurs the depth of the furrowsbeing made by the disc gang which does not encounter the surfaceirregularity is either decreased or increased due to the response of thedisc gang to the motion of the other gang, which response occurs due tothe interconnecting linkage. As this occurs the depth of plantingbecomes nonuniform with a resultant decrease in production of the landbeing planted.

This problem has been recognized and to some extent alleviated by priorart mechanisms. Thus, it is not uncommon to find incorporated into discdrills a pair of manually operated levers which independently raise orlower one or the other of the disc gangs. This type of apparatus hasbeen'found useful when there is a uniform difference in elevation of theland surface which is encountered by the grain drill, such as onhillsides and the like. However, because it is necessary to manuallymove the compensating apparatus, such apparatus does not provide apractical means for overcoming the effect of relatively limited surfaceirregularities which might be encountered by one but not the other ofthe disc gangs while the drill operator is seated on the tractor.

Until the present invention a compensating linkage which is useful forraising the lowering a pair of aligned disc gangs while at the same timeallowing relative vertical motion of the disc gangs in response tolimited irregularities on the land surface has remained an elusivedesideratum.

DESCRIPTION OF THE DRAWINGS Apparatus embodying one form of the presentinvention is disclosed in the following written description which is tobe read in conjunction with the accompanying drawings wherein likereference characters designate like parts in all views and wherein:

FIG. 1 is a generalized perspective views of a grain drill havingmounted thereon a compensating linkage which embodies the presentinvention;

FIG. 2 is a fragmentary side view taken along line 2-2 of FIG. 1 withportions of the apparatus being omitted for clarity and showing twopositions of a portion of the apparatus, one of such positions beingshown in dotted outline;

FIG. 3 is an elevational view of FIG. 2 showing the relationship of apower assembly with other elements of the compensating linkage and ofthe grain drill; and

FIG. 4 is a fragmentary perspective view of the compensating linkageshown in FIGS. 2 and 3 wherein a portion of the linkage is displaced todemonstrate the manner in which the linkage moves when a limited surfaceirregularity is encountered by one of the disc gangs on the grain drill.

GENERAL DESCRIPTION OF THE APPARATUS Turning now to the drawings and inparticular to FIG. I, there is shown a grain drill indicated generallyby the numeral 163 which includes a grain box 11 of standard designmounted by means of upright braces 12 on a frame 13 containing a frontalcrossbeam 1.4. Near the central portion of grain drill are a pair ofaxially aligned, rotatable adjusting shafts 16a and 16b which arejoumaled for rotation at their proximate ends in a common journal box17. The outer ends of the shafts are likewise rotatably journaled intojournal fittings 18a and 181;, respectively, which are carried onupright braces 12.

A pair of disc gang assemblies indicated generally by the numerals 19aand 19b are in operative engagement with adjusting shafts 16a and 16b,respectively, in a manner to be hereinafter described, whereby theindividual discs 21 of the disc gangs may be moved in a substantiallyvertical direction by incremental rotation of the adjusting shafts.

Rotation to the adjusting shafts, with resulting vertical displacementof the disc gang assemblies, is impartedby a compensating linkageassembly indicated generally by the numeral 22 which includes, amongother elements, a pair of arms 23a and 23b rigidly secured to adjustingshafts 16a and 16b, respectively. Also included within the compensatinglinkage assembly is an elongated linking means 24 and a power assembly,indicated generally by the numeral 26, which is secured to a centrallylocated frame member 27. Power assembly 26 is in operative engagementwith linking means 24 and serves to rotate the linking means and thusthe adjusting shafts 16a and 16b in a limited arc to raise and lowergang assemblies 19a and 19b. Other features of compensating linkageassembly 22 which are described hereinafter are designed to allowrelative rotation between adjusting shafts 16a and 16b while disc gangs19a and 1% are in their lowered position whereby limited independentvertical motion of the disc gang assemblies is allowed.

DETAILED DESCRIPTION OF THE GRAIN DRILL In addition to the elementsalready described as comprising a portion of the grain drill are a pairof parallel horizontal braces 28 and 29 which form a portion of frame13. A hitching yoke 31 projects outwardly from the front of grain drill10 and is held rigidly thereto by a rigid connection between the innerportions of yoke 31 with braces 28 and 29. Additional rigidity isafforded the hitching yoke by the rigid engagement of the yoke with aportion of frame member 27, at the end of which is located a tractorhitch 32. As best shown in FIG; 2, a hitch stand 33 which serves tomaintain hitching yoke 31 in a more or less horizontal position when thegrain drill is stored is secured to frame member 27 by means of amounting sleeve 34. Means, not shown, are provided for maintaining stand33 in an upward position during the period of time in which the graindrill is being operated.

A pair of pneumatic tires 36 are located at either end of grain drill 10and are attached to frame 13 by means of stub shafts 37. As the graindrill moves across the surface of the earth on tires 36, seed grainflows from grain box 11 down through a plurality of seed tubes 38 intoproximity with the forward portion of discs 21.

As may be seen most clearly in FIG. 2, disc gang assemblies 19 include aplurality of discs 21 which are rotatably joumaled on axles 39 carriedcarried at the end of pivot yokes 41. The ends of pivot yokes 41opposite axles 39 are pivotally secured to the underside of crossbeam 14by means of pivot pins 42 whereby limited rotational motion of pivotyokes 41 around the crossbeam may be provided when discs 21 are raisedor lowered. Extending upwardly from and joumaled on axles 39 arepressure rods 43 which function to push discs 21 downwardly and whichinclude an enlarged lower portion 44.

Pressure springs 46 abut the upper end of portions 44 of each.

of the pressure rods 43 and are held in compression thereon by means ofa nut 47. A yoke-shaped member, herein indentified as an elevating arm48, is utilized to raise and lower each of the pressure rods 43 and isloosely secured to each of the pressure rods at a point between theupper end of pressure spring 46 and below nut 47. By this arrangementlimited independent motion of adjacent discs is provided due to thecompression of springs 46.

Arcuate motion which raises or lowers the disc gangs is pro-- vided toelevating arms 48 by the rotation of adjusting shafts- 16a or 16b towhich elevating arms 48 are rigidly secured, as

best shown in FIG. 2. It may thus be seen when contemplating FIG. 2,that as adjusting shaft 16a is moved in a clockwise direction theelevating arms 48 secured thereon are likewise moved in a clockwisedirection to raise each of the pressure rods 43 and with them the discs21 to which they are secured. As the discs are thus raised, they arecaused to pivot in an are about crossbeam 14 due to the presence ofpivot yoke 41.

DETAILED DESCRIPTION OF THE COMPENSATING LINKAGE ASSEMBLY Compensatinglinkage assembly 22 functions to rotate adjusting shafts 16a and 16b,and to this end anns 23a and 23b are rigidly secured to shafts 16a and16b, respectively, by box couplings indicated generally by the numerals49a and 4%, respectively. The upper ends of arms 23a and 23b are in turnsecured to the outer ends of linking means 24 by ball joints 51a and51b, respectively, whereby limited universal motion between the arms 23and linking means 24 is provided whenever one of the adjusting shafts 16is rotated relative to the other of the shafts.

As best seen in FIG. 3, linking means 24 comprises a cylindrical member52 in which are slidably disposed a pair of rods 53a and 53b on whichare carried flanges 54a and 54b, respectively, for limiting the motionof rods 53 into the interior of cylindrical member 52. Ball joints 51aand 51b which are connected to arms 23a and 23b, respectively, arelocated upon and integral with rods 53a and 5312, respectively. A clevisassembly 56 mounted on the central, frontal portion of cylindricalmember 52 and includes a pivot pin 57 oriented in a direction normal tothe horizontal plane passing through the longitudinal axis of linkingmeans 24.

Power assembly 26 includes a pushrod 58, the rearward end of which issecured to cylindrical member 52 by mean of clevis assembly 56 wherebyrelative motion between the pushrod and the cylindrical member in ahorizontal plane including the longitudinal axis of the cylindricalmember is allowed. Power means, indicated generally by the numeral 59,also comprise an element of power assembly 26 and include a bellcrank 61which is pivotally secured on frame member 27 by a pivot pin 62. Anaperture 63, formed in a rearward portion of bellcrank 61, indexes witha similar aperture 64- located in frame member 27 when bellcrank 61 ismoved into its extreme 23b acting from linking means 24 through balljoints 51a and 51b, respectively. As the adjusting shafts are thusmoved, they rotate arms 48 counterclockwise and downwardly. Since apressure rod 43 is secured to the outer end of each of the elevatingarms, the pressure rods are likewise moved downwardly whereupon theirassociated discs 21 are pivoted downwardly in a clockwise direction atthe end of pivot yokes 41. In this position the grain drill may be movedacross the surface of the earth with a seed furrow being opened by eachof the discs 21 and seeds from seed tubes 38 being deposited therein.

The compensating features of the described apparatus come into playwhenever one, but not the other, of disc gang assemblies l9 encounters alimited anomaly in the surface of the earth. For purposes of example,let it'be assumed that disc gang assembly 19a encounters an elevation onthe ground. When this occurs, discs 21 associated with gang assembly 19atend to raise, thereby lifting pressure rods 43 and rotating theelevating arms associated with the pressure rods in a clockwisedirection. Upon such clockwise rotation of the elevating arms 48,adjusting shaft 160 is likewise moved in a clockwise direction due tothe rigid interconnection of elevating arms 48 with the shaft. Since arm23a is integral with shaft 16a it also moves into a clockwise arc, thuselevating ball joint 51a, as shown in FIG. 4. As ball joint 51a is movedupwardly, rod 530 is withdrawn a slight distance from the interior ofcylindrical member 52, as shown in FIG. 4. Simultaneously, cylindricalmember 52 is canted around pushrod 58 in the direction shown. Suchcanting is made possible by the universal connection between pushrod 58and power means 59 at ball joint 66.

As the described motion takes place in the a" (i.e. righthand) portionof the assembly, there will, of course, be a tendency for disc gangassembly 10b. to be moved downwardly by the linkage thereby forming adeeper furrow. Such a tendency will, of course, be reduced in relativelyhard soil; and, if the soil is sufficiently firm, may be overcometogether since the action of ball joint 51b in combination with balljoint 66 allows limited elevation of the a" end of linking means 24without a corresponding movement of rod 23b.

At such time as the surface irregularity encountered by disc gangassembly 19a is passed, the sequence outlined immediately above isreversed by the lowering of disc gang assembly 19a which results in acounterclockwise motion of adclockwise position as shown in dotted linein FIG. 2.Apin, not 5 justing shaft 16a thereby returning linking means24 to a shown, may be inserted into the thus aligned apertures tomaintain disc gang assemblies 19a and 19b in a raised, road positionwhen the disc gangs are not in use. The upper end of bellcrank 61carries a ball joint 66 to which is secured the forward end of pushrod58 whereby limited universal motion between the pushrod and thebellcrank is allowed when cylindrical member 52 is displaced due to therelative rotation between adjusting shafts 16a and 16b. At a point onbellcrank 61 subjacent ball joint 66 is secured a clevis 67 carried by ahydraulic piston assembly 68 acting thereon. Reaction support for themotion of piston assembly 68 is obtained from an upright piston mount 69on which the piston is secured by means of a clevis 71.

OPERATION The operation of the present device may best be understood byassuming that disc gang assemblies 190 and 1% are initially in theirupward, road position as shown in dotted lines in FIG. 2. Under theseconditions hydraulic piston assembly 68 is in its extended position andbellcrank 61 has been moved thereby into its extreme clockwise positionto thrust linking means 24 to the right thereby rotating adjustingshafts 16a and 16b in a clockwise position. When operations are begun onlevel ground, hydraulic piston assembly 68 is actuated to rotatebellcrank 61 counterclockwise into its full line position, as shown inFIG. 2, thereby moving pushrod 58 to the left. As this occurs, linkingmeans 24 is moved by pushrod 58 to the left and downwardly whereuponadjusting shafts 16a and 16b are moved counterclockwise by the action ofarms 23a and horizontal position, as shown in full line in FIG. 3. Itwill, of course, be understood that similar motions of the compensatinglinkage assembly take place when disc gang 1% encounters an elevationwhich is not encountered by disc gang 190. Moreover,

When it is desired to move the grain drill from one location to another,hydraulic piston assembly 68 is actuated to move bellcrank 61 in aclockwise direction thereby elevating the disc gangs in a obviousmanner.

From the above description it may be seen that the present inventionprovides means for conveniently and easily raising and lowering a pairof disc gang assemblies simultaneously and also provides an automaticcompensating motion for allowing independent vertical movement of one ofthe disc gangs relative to the other when such disc gang encounters avertical irregularity on the surface of the earth.

It should be understood that the embodiment described herein ispresented by way of example only and that many changes thereto can bemade without departing from the spirit of the invention or the scope ofthe annexed claims.

I claim:

1. In combination with a disc gang-type agricultural implement whichcomprises:

a. supported frame means having a front and back;

b. a crossbeam secured to said frame;

c. first pivot yokes each pivotally secured at one end thereof to saidcrossbeam;

d. a first disc gang means secured to the other ends of said first pivotyokes and located at a point to the side of and behind said crossbeam;

e. an upwardly extending first pressure rod having one end thereofsecured to said first disc gang means;

f. a first adjusting shaft rotatably joumaled on said frame;

g. a first elevating arm rigidly secured on said adjusting shaft and inoperating engagement with the top of said first pressure rod;

h. second pivot yokes each pivotally secured at one end thereof to saidcrossbeam;

i. a second disc gang means secured to the other end of said secondpivot yokes and in axial alignment with said first disc gang means;

j. an upwardly extending second pressure rod having one end thereofsecured to said second disc gang;

k. a second adjusting shaft rotatably journaled on said frame and inaxialalignment with said first adjusting shaft;

1. a second elevating arm secured on said first adjusting shaft and inoperative engagement with the top of said second pressure rod;

The improvement for automatically adjusting the relative erticalposition of said first and said second disc gangs which omprises;

l. elongated linking means extending along and spaced from said firstand said second adjusting shafts;

2. a universal joint carried at each end of said linking means;

3. a first arm rigidly secured to said first adjusting shaft and to oneof said universal joints;

4. a second arm rigidly secured to said second adjusting shaft and tothe other of said universal joints;

5. a power assembly mounted on said frame for moving the elongatedlinking means in an are about a portion of said adjusting shafts, saidpower assembly in operative engagement with the linking means at a pointthereon intermediate the ends thereof.

2. The apparatus defined in claim 1 wherein the power as- :mblycomprises:

a. a pushrod;

b. a clevis connecting one end of the pushrod to the linking means, saidclevis having associated therewith a pivot pin which extends normal tothe plane which includes the longitudinal axis of the pushrod and of thelinking means;

c. a hydraulic piston carried on the frame;

d. a bellcrank pivotally mounted on the frame, said bellcrank beingpivotally secured to an end of the hydraulic piston; and

e. a ball joint carried by said bellcrank at the outer end thereofopposite the pivotal connection between the bellcrank and the frame,said ball joint being operatively connected to the end of the pushrodopposite the linking means.

3. The apparatus defined in claim 1 wherein the linking means comprises:

means comprises:

a. an elongated cylinder;

b. a first rod slidably received within the interior of said cylinderand projecting therefrom from the first end thereof;

c. a second rod slidably received within the interior of said cylinderand projecting therefrom from the second end thereof; and

d. one of the universal joints carried by the linking means beingsecured at the end of said first rod opposite said cylinder and theother ,of said universal joints being secured at the end of the secondrod opposite said cylinder.

1. In combination with a disc gang-type agricultural implement whichcomprises: a. supported frame means having a front and back; b. acrossbeam secured to said frame; c. first pivot yokes each pivotallysecured at one end thereof to said crossbeam; d. a first disc gang meanssecured to the other ends of said first pivot yokes and located at apoint to the side of and behind said crossbeam; e. an upwardly extendingfirst pressure rod having one end thereof secured to said first discgang means; f. a first adjusting shaft rotatably journaled on saidframe; g. a first elevating arm rigidly secured on said adjusting shaftand in operating engagement with the top of said first pressure rod; h.second pivot yokes each pivotally secured at one end thereof to saidcrossbeam; i. a second disc gang means secured to the other end of saidsecond pivot yokes and in axial alignment with said first disc gangmeans; j. an upwardly extending second pressure rod having one endthereof secured to said second disc gang; k. a second adjusting shaftrotatably journaled on said frame and in axial alignment with said firstadjusting shaft; l. a second elevating arm secured on said firstadjusting shaft and in operative engagement with the top of said secondpressure rod; The improvement for automatically adjusting the relativevertical position of said first and said second disc gangs whichcomprises;
 1. elongated linking means extending along and spaced fromsaid first and said second adjusting shafts;
 2. a universal jointcarried at each end of said linking means;
 3. a first arm rigidlysecured to said first adjusting shaft and to one of said universaljoints;
 4. a second arm rigidly secured to said second adjusting shaftand to the other of said universal joints;
 5. a power assembly mountedon said frame for moving the elongated linking means in an arc about aportion of said adjusting shafts, said power assembly in operativeengagement with the linking means at a point thereon intErmediate theends thereof.
 2. a universal joint carried at each end of said linkingmeans;
 2. The apparatus defined in claim 1 wherein the power assemblycomprises: a. a pushrod; b. a clevis connecting one end of the pushrodto the linking means, said clevis having associated therewith a pivotpin which extends normal to the plane which includes the longitudinalaxis of the pushrod and of the linking means; c. a hydraulic pistoncarried on the frame; d. a bellcrank pivotally mounted on the frame,said bellcrank being pivotally secured to an end of the hydraulicpiston; and e. a ball joint carried by said bellcrank at the outer endthereof opposite the pivotal connection between the bellcrank and theframe, said ball joint being operatively connected to the end of thepushrod opposite the linking means.
 3. The apparatus defined in claim 1wherein the linking means comprises: a. an elongated cylinder; b. afirst rod slidably received within the interior of said cylinder andprojecting therefrom from the first end thereof; c. a second rodslidably received within the interior of said cylinder and projectingtherefrom from the second end thereof; and d. one of the universaljoints carried by the linking means being secured at the end of saidfirst rod opposite said cylinder and the other of said universal jointsbeing secured at the end of the second rod opposite said cylinder.
 3. afirst arm rigidly secured to said first adjusting shaft and to one ofsaid universal joints;
 4. a second arm rigidly secured to said secondadjusting shaft and to the other of said universal joints;
 4. Theapparatus defined in claim 2 wherein the linking means comprises: a. anelongated cylinder; b. a first rod slidably received within the interiorof said cylinder and projecting therefrom from the first end thereof; c.a second rod slidably received within the interior of said cylinder andprojecting therefrom from the second end thereof; and d. one of theuniversal joints carried by the linking means being secured at the endof said first rod opposite said cylinder and the other of said universaljoints being secured at the end of the second rod opposite saidcylinder.
 5. a power assembly mounted on said frame for moving theelongated linking means in an arc about a portion of said adjustingshafts, said power assembly in operative engagement with the linkingmeans at a point thereon intErmediate the ends thereof.